Hydrangea

what type of nails do you use ??

i've got 2 pink plants and would love to be able to turn 1 blue xx

Kimmy - Since I took this picture which is not very good anyway, the colour has become "bluer". I am not good on nails, just ordinary maybe they are called timber nails, about 8 cm long. But I must add that originally it was a blue Hydrangea, only last year, I had very few flower heads and they were pink. So I dont really know if the nails did the trick, or if it would have happened anyway, I certainly didn't change the soil. Oh and by the way I also took a cutting and they are pink, so try it, it cant hurt. Good luck